At 30,000 words and 104 pages, Colm Tóibín's The Testament of Mary can be read in an afternoon – but it is unquestionably a novel, Man Booker judges said on Tuesday, as it became the most slender work to be shortlisted for the £50,000 prize.

Six books were named on a list striking for its international diversity. As well as Tóibín's imagining of the mourning of Mary after Jesus's crucifixion, there were novels featuring the destruction of an English village, one girl's escape from Zimbabwe to Detroit, a communist insurgency in Kolkata, the New Zealand gold rush, and bullying and Buddhism in Japan.

The chair of judges, Robert Macfarlane, said they had been drawn to novels that "sought in some way to extend the power and possibility of the form".

He added: "This is a shortlist that shows the English language novel to be a form of world literature. It is a shortlist that crosses continents, joins countries and spans the centuries." If anything connected the works, he said, it was that they were all about ways of relating. "They are all, all about the strange ways people are brought together and the painful ways in which they are held apart."

Harvest by Jim Crace was on the shortlist, to no one's surprise, and remains the bookmakers' favourite to win. It is a dark, often horrifying story of fear and superstition set at a time when peasant farmers were being forced from the land. It is Crace's second shortlisting, for a novel that is probably, he says, his last.

Women outnumber men on the shortlist for the first time since 2006. They are Eleanor Catton, at 28 the youngest writer, for her 832-page epic The Luminaries; Ruth Ozeki, an ordained Buddhist priest, for A Tale for the Time Being; Jhumpa Lahiri, who was appointed to the president's committee on the arts and humanities by Barack Obama, for The Lowland; and NoViolet Bulawayo, the only debut novelist, for We Need New Names.

Macfarlane said there had been "an exhausting number of child narrators" among this year's entries, but none stood out like Bulawayo's creation, Darling. The writer is the first Zimbabwean shortlisted for the prize. Speaking from a hotel in Cape Town, South Africa, where she is promoting her novel, she said: "I'm over the moon. It's one of those things that leaves you speechless; I'm one of those people who can't scream. I'm sure it will sink in over the next few days. It's a huge honour and I feel very encouraged."

For Tóibín, it is the third time on the Booker shortlist following The Blackwater Lightship in 1999 and The Master in 2004. The Testament of Mary has been warmly received by critics, although a Broadway stage version, with Fiona Shaw as Mary, closed after just 27 previews and 16 performances.

The judge Robert Douglas-Fairhurst said it was easy to get hung up on whether something was a novel or novella or short story or even a novelette. There were many reasons that Tóibín's book qualified as a novel. "Yes it is compact, but it is also dense and it is far-reaching. This is a short novel but one we felt is long in the memory."

The judges whittled down the 152 entries to six in an amicable fashion, Macfarlane said. "The judging process was a great pleasure. The carpet remains unbloodied, there were no flare-ups, no put-downs, no walkouts, no punch-ups."

The other judges this year are the BBC broadcaster Martha Kearney, the classicist and critic Natalie Haynes, and the former literary editor of Scotland on Sunday Stuart Kelly. The winner of the £50,000 prize will be named on 17 October.